This invention relates to a machine head for tuning a stringed instrument especially a guitar or the like. Traditionally the guitar string is tensioned and tuned using a `machine head` which consists of a vertical spindle which can be rotated by means of a worm gear-cog assembly. The `machine head` is fixed to the head of the guitar and the string is fed through a hole in the spindle and is wound onto it using the worm gear-cog system. The string is thus tensioned as the other end is fixed immovably at the body end of the guitar. Tensioning continues until the right musical note is sounded.
The drawback of the traditional system is that slackness between the cog and the worm can cause tuning slip and unprecise tuning. It has been accepted without question that a worm drive is required to provide sufficient adjustment and consequently the above system has become universally accepted for guitars or the like despite the short comings.